1. Field of the Invention
The present invention relates to charging devices and more particularly to a charging device capable of outputting a selected one of a plurality of voltages to one of various portable electronic devices being connected.
2. Description of Related Art
Many current portable electronic devices such as mobile phones, digital cameras, notebook computers, camcoders, Walkmans, personal digital assistants (PDAs), or even some toys are powered by one or more batteries. The batteries could be rechargeable ones that can be recharged by a charging device. Conventionally, an output voltage value of charging device is fixed after being manufactured. In a charging operation, a consumed battery of the electronic device is placed in a charger. Next, alternating current from an external source is rectified into a direct current having a fixed voltage value by a rectification circuit of the charger prior to charging the battery. It is understood that different portable electronic devices may have different operating voltages. Moreover, the same electronic devices (e.g, mobile phones) made by different manufacturers may have different operating voltages. It is often that each portable electronic device has its own charger. Thus, it is possible that a person having, for example, 10 such portable electronic devices may also have 10 chargers since output voltage values of all 10 chargers are different each other. So many chargers may cause confusion to users while using. Further, precious storage space is occupied by the chargers, resulting in a messy storage space. Furthermore, to maintain the chargers is a waste of time and money.
Thus, it is desirable to provide a novel charging device with selectable output voltage values in order to overcome the above drawbacks of prior art.
It is an object of the present invention to provide a charging device capable of outputting a selected one of a plurality of voltages to one of various portable electronic devices being connected. By utilizing this, advantages such as adaptability by possessing only one charging device, convenience, and space saving are obtained.
It is another object of the present invention to provide a charging device being connectable to either external power source or automobile power supply depending on applications. Hence, it is convenient in use.
To achieve the above and other objects, the present invention provides a charging device comprising a voltage stabilization unit for maintaining a stable voltage output as receiving a rectified direct current (DC) voltage from an output of an adaptor; a charging unit coupled to an output of the voltage stabilization unit so as to control an on-off of the device and detect a charge level of a rechargeable battery being charged; a battery protection unit coupled to both an output of the charging unit and the battery so as to cut off the charging unit when an either over charging or over discharging of the battery occurs; and a voltage setting unit coupled to an output of the battery protection unit and including a switch being operative to select one of a plurality of output voltages of the battery protection unit.